Role of ultrasonography for assessing optimal placement of supraglottic airway devices: A review of literature

Supraglottic airway devices (SADs) have revolutionised perioperative airway management. These devices have contributed significantly to airway management, especially in the context of anticipated or unanticipated difficult airway, thereby decreasing airway-related morbidity. The use of these devices is now accepted even for positive pressure ventilation due to better seal and modifications (such as a double cuff or cuff material) preventing gastric insufflation with lesser chances of regurgitation. The quality of seal depends on how accurately the cuff matches the dimensions of the laryngeal inlet. Various methods and techniques are used for confirming the optimal placement of SADs with variable success rate. Evaluation based on conventional clinical tests is most commonly used for assessing the correct placement of SADs. However, clinical tests have been associated with limited outcome as they may not definitely be able to detect improper placement of SAD. Malpositioning may increase the incidence of complications such as altered airway dynamics, gastric insufflation, regurgitation and aspiration of gastric contents. The accuracy of these tests to identify malposition has been questioned by recent studies where fibreoptic evaluation of position of SAD identified many unacceptable placements which had been considered acceptable on the basis of clinical tests. Another limitation of these tests is that they fail to provide anatomic evidence of optimal SAD placement. Thus, other methods are required to confirm SAD position to avoid adverse events related to the airway. This review elaborates on the use of ultrasound to assess the optimal placement of supraglottic airway devices.